git:20260318.e6a0e19 to git:20260320.d98f3cb

---

name: nw-hexagonal-testing

description: 5-layer agent output validation, I/O contract specification, vertical slice development, and test doubles policy with per-layer examples

disable-model-invocation: true

---

# Hexagonal Testing and Output Validation

## 5-Layer Output Validation Framework

Validates agent OUTPUTS, not TDD testing methodology.

### Layer 1: Unit Testing (Output Validation)

Validate individual software-crafter outputs.

```yaml

structural_checks:

- required_elements_present: true

- format_compliance: true

- quality_standards_met: true

quality_checks:

- completeness: "All required components present"

- clarity: "Unambiguous and understandable"

- testability: "Can be validated"

test_data_quality:

real_data: "Use real API responses as golden masters"

edge_cases: "Test null, empty, malformed, boundary conditions"

assertions: "Assert expected counts, not just 'any results'"

```

### Layer 2: Integration Testing (Handoff Validation)

Validate handoffs to next agent. Next agent must consume outputs without clarification.

- Deliverables complete: all expected artifacts present

- Validation status clear: quality gates passed/failed explicit

- Context sufficient: next agent can proceed without re-elicitation

### Layer 3: Adversarial Output Validation

Challenge output quality through adversarial scrutiny of generated code:

- SQL injection vulnerabilities? | XSS vulnerabilities? | Null/undefined/empty input handling?

- Integer overflow/underflow? | Graceful failure vs crash? | Exception handling appropriateness?

Pass criteria: all critical challenges addressed, edge cases documented and handled.

For peer review and escalation protocols, load the review-dimensions skill.

## Input/Output Contract

### Inputs

- **Required**: user_request (non-empty command string) | context_files (existing readable file paths)

- **Optional**: configuration (YAML/JSON) | previous_artifacts (outputs from prior wave for handoff)

### Outputs

- **Primary**: code artifacts (src/**/*, strictly necessary only) | documentation (docs/develop/, minimal essential)

- **Secondary**: validation_results (gate pass/fail status) | handoff_package (deliverables, next_agent, validation_status)

- **Policy**: any document beyond code/test files requires explicit user approval before creation

### Side Effects

- **Allowed**: file creation (src/**, tests/** only) | file modification with audit trail | log entries

- **Forbidden**: unsolicited documentation | deletion without approval | external API calls | credential access

- **Requires permission**: documentation beyond code/test files | summary reports | analysis documents

### Error Handling

- Invalid input: validate first, clear error, do not proceed with partial inputs

- Processing error: log context, return to safe state, actionable user message

- Validation failure: report failed gates, withhold artifacts, suggest remediation

## Vertical Slice Development

Complete business capability per slice: UI -> Application -> Domain -> Infrastructure for a specific feature. Slices developed and deployed independently. Focus on business capability over technical layer.

For test doubles policy and violation examples, load the tdd-methodology skill.